Furnace door



W. G. NICHOL FURNACE DOOR June 19, 1951 Filed June 17, 1948 INVENTOR. WILBERT G. N \CHOL.

ATTORN EY Patented June 19, 1951 FURNACE DOOR Wilbert G. Nichol, Pittsburgh, Pa., assignor to United States Steel Company, a corporation of New Jersey Application June 17, 1948, Serial No. 33,560

8 Claims. I

This invention relates to furnace doors of the water-cooled, monolithic refractory lined type, and particularly to improved lining plates embodied in such doors.

Commonlyv these doors comprise an outer water-cooled shell, a lining plate inside the shell, and a lining of monolithic refractory material, such as rammed plastic chrome, supported by the lining plate. In previous doors with which I am familiar, the lining plate has studs which protrude toward the furnaceinterior and support 7 the refractory lining and conduct heat therefrom. The refractory lining has a relatively short life and, as the lining wears away, the ends of the studs burn off. When the door is re-lined, practically all of the studs must be replaced.

An object of the present invention is to provide improved lining plates which cool refractory lin-,

ings more efiectively than previous lining plates with which I am familiar, and thus prolong the life of these linings.

A further object of the invention is to provide lining plates of an improved design which renders them less susceptible to damage from furnace heat than previous lining plates with which I am familiar, and thus may be re-used through the life of several refractory linings.

A further object of the invention is to provide improved lining plates which have integral hollow water-cooled knobs for anchoring the refractory lining, the knobs furnishing better mechanical anchoring means, as well as better heat conduction means than the studs previously used.

In accomplishing these and other objects of the invention I have provided improved details of structure, a preferred form of which is shown in the accompanying drawing, in which:

Figure 1 is an interior side elevational view of an improved furnace door embodying features of the present invention, the refractory lining being partly broken away to illustrate the novel lining plate; and

Figure 2 is a vertical sectional view of the door taken substantially on line II 1I of Figure 1.

Referring more in detail to the drawing:

The furnace door illustrated comprises the usual water-cooled she l I, a lining plate l2 embodying features of the present invention, and the usual monolithic refractory lining l3, which may be of any suitable material such as plastic chrome. The door has the usual wicket or peep hole It. If desired, the door may have indicator holes I 5, which glow when the lining becomes thin and thus. indicate the need to re-line the door, as known in the art.

Lining plate l2 includes a body or base It, a rim I1 surrounding the base, a marginal flange 88 surrounding the rim, and a plurality of hollow knobs l9 protruding from the base toward the interior of the furnace. The outer edges of the marginal flange are welded to shell It, as indicated at 20, and the body of the plate is spaced from the shell to furnish a water chamber. Rim I! has an interiorly directed bead 2| that assists in anchoring refractory lining l3. Base it has an annular boss 22 surrounding the wicket to which a wicket cone 23 is welded.

Lining plate I 2 preferably is an integral casting of steel or other metal that can be welded readily. If desired, the casting may be of an alloy more resistant to furnace temperatures and to corrosive effects of the cooling water than plain carbon steel, although I have found the latter satisfactory for most purposes. A casting is preferred to a rolled on stamped plate, since there is less warpage. Preferably knobs l9 are in straight horizontal rows and the knobs in alternate rows are staggered, as shown in Figure 1. This arrangement enables patterns made for casting I large lining plates to be blocked off for casting smaller plates, thus eliminating the need for separate patterns for each door size.

As shown in Figure 2,' each knob is a hollow body of substantially circular cross section and tapering slightly toward its outer extremity. The junctures between the base and the knobs are rounded as indicated at 24, preferably being formed with a substantial radius. The knob tips also are rounded, preferably being substantially hemispherical. The taper and the rounded junctures and tips facilitate casting the lining, as well as furnishing better'water circulation and cooling, as hereinafter explained. The outer walls of the knobs carry integral annular fins or beads 25, which furnish a mechanical anchoring means for the lining and also promote cooling of the lining. Initially the lining depth is. suflicient to cover the entire knobs,.but as the lining wears the knob'tips become exposed. r r

In operation, cooling water is circulated through shell l0, preferably being admitted at one of the lower corners and discharging at the upper corner diagonally opposite. The cooling water fills the entire shell and knobs l9.* The knob tips are more exposed to furnace heat than the rest of the lining plate and hence are hotter. The temperature differential between base l6 and the knob tips produces a continuous water circulation through each knob. The rounded junctures and tips furnish a smooth pathway 3 for the water and reduce turbulence in the flow. The regions of thelining surface most remote from the knob tips are sufficiently close to cooling water that they are maintained at a temperature which the lining material can withstand. The rounded J'unctures between the base and the knobs assist in reducing this distance. The rounded knob tips expose a minimum of plate area to furnace heat and such area as is exposed is effectively cooled. Fins conduct heat from the refractory lining as well as anchoring the lining to the door. a

I have found that the improved lining plate of the present invention materially prolongs the life of each refractory lining over other lining plates with which I am familiar. When replacement of the lining does become necessary, the lining plate still is substantially undamaged and serves through the life of several linings. As the knob tips eventually become burned, they can be repaired readily by welding on additional metal.

While I have shown and described only a single embodiment of the invention, it is apparent that modifications may arise. Therefore, I do not wish to be limited to the disclosure set forth, but only by the scope of the appended claims.

I claim:

1. A lining plate for water-cooled, monolithic refractory lined furnace doors including a base, marginal means surrounding said base and adapted to be afllxed to a door shell, a plurality of hollow knobs protruding from said base, the tips of said knobs and the junctures between said base and said knobs being rounded, and fins on the outside walls of said knobs intermediate their length adapted to anchor a lining thereto, said lining plate being an integral steel casting.

2. A lining plate for water-cooled, monolithic refractory lined furnace doors including a base, a rim surrounding said base, a marginal flange surrounding said rim and adapted to be' welded to a door shell, a plurality of hollow knobs protruding from said base and being of substantially circular cross section and tapering slightly from said base, the tips of said knobs and the junctures between said base and said knobs being rounded, and annular fins surrounding the outside walls of said knobs intermediate their length adapted to anchor a lining thereto, said lining plate being an integral steelcasting.

3. A lining plate for water-cooled, monolithic refractory lined furnace doors including a base, marginal means surrounding said base and adapted to be aflixed to a door shell, a plurality of hollow knobs protruding from said base and being arranged in straight rows with alternate rows staggered, the tips of said knobs and the junctures between said base and said knobs being rounded, and annular fins surrounding the outside walls of said knobs intermediate their length adapted to anchor a lining thereto, said lining plate being an integral steel casting.

4. A lining plate for water-cooled, monolithic refractory lined furnace doors including a base, marginal means surrounding said base and adapted to be affixed to a door shell, said base having a wicket opening, an annular boss surrounding said wicket opening, a plurality of hollow knobs protruding from said base, the tips of said knobs and the junctures between said base and said knobs being rounded, and annular fins surrounding the outside walls of said knobs intermediate their length adapted to anchor a 4 lining thereto, said lining plate being an integral steel casting. I

5. A lining plate for water-cooled, monolithic refractory lined furnace doors including a base, a

. rim surrounding said base, a marginal flange surrounding said rim and adapted to be welded to a door shell, said base having a wicket opening, an annular boss surrounding said wicket opening, a plurality of hollow knobs protruding from said base and being arranged in straight rows with alternate rows staggered, said knobs being of substantially circular cross section and tapering slightly from said base, the tips of said knobs and the junctures between said base and said knobs being rounded, and annular fins surrounding the outside walls of said knobs intermediate their length adapted to anchor a lining thereto, said lining plate being an integral steel casting.

6. In a furnace door, an outer shell, a lining plate welded at its edges to said shell and spaced therefrom to furnish a water chamber, and a refractory lining supported on said lining plate, said lining plate being an integral steel casting and including a plurality of hollow knobs protruding from the body of the plate into said refractory lining, the tips of said knobs and the junctures between the body of the plate and the knobs being rounded, and integral fins on said knobs intermediate their length anchoring said refractory lining.

7. In a furnace door, an outer shell, a lining plate welded at its edges to said shell and spaced therefrom to furnish a water chamber, and a refractory lining supported on said lining plate, said lining plate being an integral steel casting and including a plurality of hollow knobs of substantially circular cross section, tapering from the body of the plate and protruding into said refractory lining, the tips of said knobs and the junctures between the body of the plate and the knobs being rounded, and integral annular fins on said knobs intermediate their length anchoring said refractory lining.

8. In a furnace door, an outer shell, a lining plate, and a refractory lining, said lining plate including a base, marginal means surrounding said base and welded to said shell, said base being spaced from said shell to furnish a water chamber, a plurality of hollow knobs integral with the base and protruding into said refractory lining, the knob tips and the junctures between said base and said knobs being rounded, and integral fins on said knobs intermediate their length anchoring said refractory lining.

WILBERT G. NICHOL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Date 

